The invention concerns a resonator assembly for generating ignition energy for the combustion of gas mixtures, which in a manner known in the art as a functional element includes a generator in a generator section, a voltage increase being sought by suitable excitation in an oscillating circuit encompassed thereby, a resonator section mounted functionally behind the generator section and electromagnetically coupled thereto and having a further oscillating circuit which for this purpose includes at least one inductance, and an ignition section.
In the resonator coupled to the generator, a voltage superelevation is to arise during operation, which with the continuous supply of energy from the generator can attain 100 to 200 times the voltage fed to the resonator from the generator, while in the section in front, that is, in the generator, the voltage increase attainable there is usually 2-3 times the operating voltage applied. The oscillating circuits of generator and resonator, that is, the inductances and capacitances encompassed thereby, here function as energy storage devices, previously supplied energy being at least temporarily stored in a magnetic field of the respective inductance and cyclically converted to electrostatic energy in a capacitance assigned to the inductance or associated with the inductance due to component specifics or geometry. In case of resonance superelevation, at outputs of the resonator in particular due to suitable geometrical design of housing or housing elements there is arcing, that is, plasma formation, which in an internal combustion engine is used in a manner known in the art to ignite an air/fuel mixture.
Resonator assemblies of this kind are known in the art, and reference is made to DE 10 2006 037 246 A 1, DE 10 2005 037 420 A1 and EP-A-1 662 626, for example. The resonator assembly functions here as an energy storage device, previously supplied energy being at least temporarily stored in a magnetic field of the resonator assembly and cyclically converted to electrostatic energy of a capacitance associated with the resonator assembly. The resonator assembly includes a generator and a resonator mounted behind the latter, both the generator and the resonator each comprising an oscillating circuit, that is, a capacitance coupled to an inductance. On excitation of the oscillating circuit on the generator side, a voltage increase occurs in the latter in a manner known in the art, attaining e.g. two or three times the operating voltage applied. In the resonator coupled to the generator, on the other hand, a voltage superelevation occurs, which if energy is continuously supplied from the generator can perfectly well attain one hundred to two hundred times the voltage fed to the resonator from the generator.
A drawback of the resonator assemblies known in the state of the art lies above all in that electromagnetic parameters are not known in a manner required for optimum generation of plasma in the region of the spark gap. For example, with the solution according to the above-mentioned DE 10 2005 037 420 there is no spatial limitation of the magnetic field of the resonator assembly there, so that this is influenced by material located in the environment as well. With the resonator assembly described in DE 10 2006 037 246, a disadvantage also lies in that, due to the connection of the generator, a point between the inductance and capacitance of the generator is kept at earth potential, so that in an unfavourable manner the desired resonant frequency is influenced by external magnetic materials because the magnetic field is not spatially limited. Furthermore, there may also be an effect on articles located in spatial proximity to the resonator assembly, e.g. heating. Lastly, known solutions also seem to neglect protection against the high voltage arising, or it is attempted to achieve possible protection by external means, e.g. a cap, a sleeve or the like. In EP-A-1 662 626 only an inductance section and a capacitance section are shielded by a housing or a casing.